Display device

ABSTRACT

A display device includes a display panel, a touch panel control unit, a plurality of scanning electrodes formed on the display panel, a plurality of detection electrodes formed on the display panel so as to intersect with the plurality of scanning electrodes, a drive signal supply unit for inputting a drive signal to each of the scanning electrodes, and a detection unit for detecting a detection signal from each of the detection electrodes. The touch panel control unit supplies the driving signal to each of the scanning electrodes from the drive signal supply unit to enable detection of a touch position of a detection object based on the detection signal detected, and supplies the driving signal to all of the scanning electrodes collectively from the drive signal supply unit to enable detection of approach of the detection object to the touch panel based on the detection signal detected.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. application Ser.No. 13/851,144, filed Mar. 27, 2013, the contents of which areincorporated herein by reference.

The present application claims priority from Japanese applicationJP2012-095405 filed on Apr. 19, 2012, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device, particularly, to atechnique that is effective for the application to a display deviceequipped with a touch panel in which a liquid crystal panel is equippedwith a touch panel function.

2. Description of the Related Art

A display device including a device referred to as a touch sensor or atouch panel, which performs a touch operation (a contact pressingoperation, hereinafter, simply referred to as a touch) on a displayscreen using a finger of a user, a pen or the like to input information,has been used for a mobile electronic apparatus such as a PDA and aportable terminal, various home electric appliances, an automated tellermachine or the like. As such a touch panel, a resistive membrane type ofdetecting a resistance valve change of a touched portion, anelectrostatic capacity type of detecting a change of the capacity, anoptical sensor type of detecting a change of an amount of light or thelike have been known.

The touch panel of the electrostatic capacity type is provided withscanning electrodes (Y electrodes) for a drive signal application placedlengthwise and breadthwise in a two dimensional matrix form, anddetection electrodes (an X electrodes) for signal detectionperpendicular to the scanning electrodes, and the capacity of eachelectrode is detected in an input processing unit. When a conductor suchas a finger comes into contact with the surface of the touch panel,since the capacity of each electrode increases, the input processingunit detects the increase, and calculates the input coordinate on thebasis of the signal of the change of the capacity detected by eachelectrode.

SUMMARY OF THE INVENTION

For example, in the touch panel-integrated display device in which thetouch panel is built in the liquid crystal display panel, a commonelectrode for display (also referred to as a counter electrode)originally included in the liquid crystal display panel is also used asone electrodes (drive electrodes) of a pair of electrodes for touchsensor, and the other electrodes (detection electrodes for sensor)thereof is formed on a glass substrate.

In such a touch panel-integrated display device, a new usage method isassumed in which, if it is possible to detect the approach of a finger(an detection object) of a user, when the finger of the user approaches,a menu screen is displayed on the display screen of the touchpanel-integrated display device.

When assuming such a usage method, in the touch panel-integrated displaydevice, it is requested that a detection circuit, which is used for atype of performing the high-precision coordinate detection (hereinafter,also referred to as a mutual detection) which uses the change of theelectrostatic capacity between the common electrode and the detectionelectrode due to the influence of a finger of a user, can also be usedfor a type of detecting the presence or absence of the approach of thedetection object without coordinate information (hereinafter, alsoreferred to as a self detection) which uses a change of an earthcapacity of the detection electrode due to the influence of a finger ofa user.

The invention was based on the above-mentioned demand, and an objectthereof is to provide a technique that makes the detection circuit,which is used for the mutual detection, also be used for the selfdetection, in the touch panel-integrated display device.

The above-mentioned and other objects and new characteristics of theinvention will be clarified by the description of the specification andthe attached drawings.

A representative summary of the inventions disclosed in the presentapplication will be briefly described as below.

(1) According to an aspect of the invention, there is provided a displaydevice that includes a display panel, and a touch panel integrated inthe display panel, wherein the touch panel has a plurality of scanningelectrodes formed on the display panel; a plurality of detectionelectrodes that is formed on the display panel and intersects with theplurality of scanning electrodes; drive signal supply unit for inputtinga drive signal to each of the scanning electrodes; detection unit foracquiring a detection signal from each of the detection electrodes;touch position detection unit for detecting a touch position of andetection object, based on the detection signal detected from each ofthe detection unit, when the drive signal is sequentially input to eachof the scanning electrodes from the drive signal supply unit; andapproach detection unit for detecting that the detection objectapproaches the touch panel, based on the detection signal detected fromeach of the detection unit, when a scanning voltage is collectivelyinput to all the scanning electrodes from the drive signal supply unit.

(2) In the display device according to (1), the drive signal supply unithas a switching element S1 that supplies a drive voltage Vtxh to each ofthe plurality of scanning electrodes, and a switching element S2 thatsupplies a drive voltage Vtxl (Vtxl<Vtxh) to each of the plurality ofscanning electrodes, the detection unit has an integration circuit inwhich a reference voltage Vref is input to one terminal, a switchingelement S3 that is connected between each of the detection electrodesand the other terminal of the integration circuit, and a switchingelement S4 that is connected between each of the detection electrodesand the one terminal of the integration circuit, the switching elementS1 and the switching element S2 are provided for each of the scanningelectrodes, and the integration circuit, the switching element S3 andthe switching element S4 are provided for each of the detectionelectrodes.

(3) In the display device according to (2), a touch position detectionperiod of the detection object has a reset period and a detection periodfor each of the scanning electrodes, in the reset period in a scanningelectrode of a scanning target to which the drive signal is input, theswitching element S1 of the scanning electrode of the scanning target isturned off, the switching element S2 of the scanning electrode of thescanning target is turned on, the switching element S1 and the switchingelement S2 of the scanning electrode other than the scanning target areturned off, the switching elements S3 of all the detection electrodesare turned off, and the switching elements S4 of all the detectionelectrodes are turned on, the capacity between the scanning electrode ofthe scanning target and all the detection electrodes is charged with avoltage of (Vref−Vtxl), in the detection period, the switching elementS1 of the scanning electrode of the scanning target is turned on, theswitching element S2 of the scanning electrode of the scanning target isturned off, the switching element S1 and the switching element S2 of thescanning electrode other than the scanning target are turned off, allthe switching elements S3 are turned on, all the switching elements S4are turned off, and the electric current flowing in the capacity betweenthe scanning electrode of the scanning target and all the detectionelectrodes is integrated by the integration circuit provided for each ofthe detection electrodes, and the touch position detection unit detectsthe touch position of the detection object, based on the output voltageof the integration circuit provided for each of the detectionelectrodes.

(4) In the display device according to (2), the approach detectionperiod of the detection object has a reset period, a charge period, anda detection period, during the reset period, the switching elements S1of all the scanning electrodes are turned off, the switching elements S2of all the scanning electrode are turned on, the switching elements S3of all the detection electrodes are turned off, and the switchingelements S4 of all the detection electrodes are turned on, the capacitybetween all the scanning electrodes and all the detection electrodes ischarged with a voltage of (Vref−Vtxl), during the charge period, theswitching elements S1 of all the scanning electrodes are turned on, theswitching elements S2 of all the scanning electrodes are turned off, theswitching elements S3 of all the detection electrodes are turned off,and the switching elements S4 of all the detection electrodes are turnedoff, the capacity between all the scanning electrodes and each of thedetection electrodes is charged with a voltage of (Vref−Vtxl+Vtxh),during the detection period, the switching elements S1 of all thescanning electrodes are turned on, the switching elements S2 of all thescanning electrodes are turned off, the switching elements S3 of all thedetection electrodes are turned on, and the switching elements S4 of allthe detection electrodes are turned off, the capacity between all thescanning electrodes and each of the detection electrodes is integratedby the integration circuit provided for each of the detectionelectrodes, and the approach detection unit detects that the detectionobject approach, based on the output voltage of the integration circuitprovided for each of the detection electrodes.

Effects obtained by the representative aspect of the inventionsdisclosed in the present application are described as follows.

According to the invention, in the touch panel-integrated displaydevice, the detection circuit used for the mutual detection can also beused for the self detection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are views that describe a touch panel display device ofthe related art.

FIGS. 2A and 2B are views that describe the touch panel shown in FIGS.1A and 1B.

FIG. 2C is a view that describes a detection sequence of the touch panelshown in FIGS. 1A and 1B.

FIGS. 3A and 3B are views that describe a display device equipped with atouch panel of the related art.

FIGS. 4A and 4B are views for describing the touch panel shown in FIGS.3A and 3B.

FIGS. 5A, 5B and 5C are views that describe a detection principle of aliquid crystal touch panel-integrated display device having thestructure shown in FIGS. 4A and 4B.

FIGS. 6A and 6B are views that describe a mutual detection in the touchpanel-integrated display device.

FIGS. 7A and 7B are views that describe the control of the selfdetection of the present example in the touch panel-integrated displaydevice.

FIGS. 8A and 8B are views that describe the detection state of the selfdetection of the present example in the touch panel-integrated displaydevice.

FIG. 9 is a perspective view that shows a more specific configuration ofthe touch panel-integrated display device of an example of theinvention.

FIG. 10 is a view that describes a counter electrode and a detectionelectrode in the liquid crystal touch panel-integrated display deviceshown in FIG. 9.

FIG. 11 is a cross-sectional view that shows a part of a cross sectionof a display unit of the liquid crystal touch panel-integrated displaydevice shown in FIG. 9 in an enlarged manner.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an example of the invention will be described in detailreferring to the drawings.

In addition, in the whole drawings for describing the example, elementshaving the same functions are denoted by the same reference numerals,and the repeated description will be omitted. Furthermore, the followingexample does not limit the interpretation of the claims of theinvention.

Summary of Touch Panel of Related Art

FIGS. 1A and 1B are views for describing a touch panel display device ofthe related art.

FIG. 1A is a block diagram that shows a schematic configuration of thetouch panel display device of the related art, and FIG. 1B is a viewthat shows a structure of the touch panel display device of the relatedart.

In the touch panel display device shown in FIGS. 1A and 1B, as shown inFIG. 1B, an electrostatic capacity type touch panel 106 is bonded on adisplay panel (herein, a liquid crystal display panel) 101 by anadhesive 110. As will be described later, the touch panel 106 has a Yelectrode for drive signal application (a scanning electrode) and an Xelectrode for signal detection (a detection electrode) perpendicular tothe Y electrode.

The touch panel 106 is provided on a front surface of the display panel101. Thus, when a user sees images displayed on the display panel 101,since the display images need to penetrate the touch panel 106, it ispreferable that the touch panel 106 have high optical transmittance.

The X electrode and the Y electrode of the touch panel 106 are connectedto a touch panel control unit 108 through a wiring 107.

The touch panel control unit 108 sequentially applies the drive signalusing the Y electrode as a scanning electrode, and measures the capacitybetween the electrodes on an intersection point of each electrode usingthe X electrode as a detection electrode, and calculates and obtains theinput coordinates from the capacity detection signal that changesaccording to the capacity value of the point of intersection between therespective electrodes.

The touch panel control unit 108 transmits the input coordinate to asystem control unit 105 using an I/F signal 109.

When the input coordinate is transmitted from the touch panel 106 by thetouch operation, the system control unit 105 generates the display imagedepending on the touch operation, and transmits the display image to adisplay control circuit 103 as a display control signal 104.

The display control circuit 103 generates a display signal 102 dependingon the display image transmitted by the display control signal 104, anddisplays the images on the display panel 101.

In addition, as the display panel, a panel capable of using the touchpanel 106 may be used, and a display panel that uses an organic lightemitting diode element and a surface conduction type electron emissionelement, an organic EL display panel or the like can also be used,without being limited to a liquid crystal display panel.

FIGS. 2A and 2B are views for describing the touch panel 106 shown inFIGS. 1A and 1B.

FIG. 2A is a view that shows an electrode pattern of the touch panel 106shown in FIGS. 1A and 1B, and FIG. 2B is a cross-sectional view thatshows a cross-sectional structure along a cut line A-B of FIG. 2A.

As shown in FIG. 2A, the touch panel 106 shown in FIGS. 1A and 1B has anX electrode 201 and a Y electrode 202 for detecting the capacity.Herein, for example, although five X electrodes 201 and six Y electrodes202 are shown, the number of the electrodes is not limited thereto.

In FIG. 2B, reference numeral 204 is a touch panel substrate formed of aglass substrate, a PET film or the like. The touch panel 106 shown inFIGS. 1A and 1B is configured so that the X electrode 201 and the Yelectrode 202 are formed on the touch panel substrate 204, and aprotective membrane 203 is formed on the X electrode 201 and the Yelectrode 202. Furthermore, in FIG. 2B, a shield electrode 205 is formedon a surface of the display panel side of the touch panel substrate 204.

FIG. 2C is a view for describing the detection sequence of the touchpanel 106 shown in FIGS. 1A and 1B, and for describing the detectionsequence when there is no input to the touch panel 106. Furthermore,FIG. 2C is a wave form view. In the wave form view shown in FIG. 2C, ahorizontal axis indicates a time and a vertical axis indicatesamplitude.

As shown in FIG. 2C, a drive voltage (a drive pulse) 401 is sequentiallyapplied to the Y electrode 202 of TX1 to TX6 for each scanning period.On the contrary, the wave form of a detection signal 402 detected by theX electrode 201 of RX1 to RX5 changes in synchronization with the inputof the drive voltage. In FIG. 2C, since there is no input to the touchpanel 106, the amplitude of the detection signal detected by the Xelectrode 201 of RX1 to RX5 is not greatly changed.

In addition, as shown in A of FIG. 2C, the drive signal (the inputpulse) 401 which is sequentially input to the Y electrode 202 of TX1 toTX6 for each detection period is a plurality of pulse rows. Similarly,as shown in B of FIG. 2C, the detection signal 402 detected by the Xelectrode 201 of RX1 to RX5 is also a plurality of pulse rows.

FIGS. 3A and 3B are views for describing the touch panel-integrateddisplay device of the related art.

FIG. 3A is a block diagram that shows a schematic configuration of thetouch panel-integrated display device of the related art, and FIG. 3B isa view that shows a cross-sectional structure of the touchpanel-integrated display device of the related art.

In the touch panel-integrated display device shown in FIGS. 3A and 3B,as shown in FIG. 3B, an electrostatic capacity type touch panel 301 isformed inside the display panel (herein, the liquid crystal displaypanel) 101. Other configurations are the same as those of FIG. 1A, andthe repeated detailed description thereof will be omitted.

FIGS. 4A and 4B are views for describing the touch panel 301 shown inFIGS. 3A and 3B, FIG. 4A is a view that shows an electrode pattern ofthe touch panel 301 shown in FIGS. 3A and 3B, and FIG. 4B is across-sectional view that shows a cross-sectional structure along a cutline A-B of FIG. 4A.

As shown in FIG. 4A, the touch panel 301 shown in FIGS. 3A and 3B hasthe X electrode 201 and the Y electrode 202 for detecting the capacity.Herein, for example, although the five X electrodes 201 and the seven Yelectrodes 202 are shown, the number of the electrodes is not limitedthereto.

In FIG. 4B, reference numeral 211 is a first substrate, referencenumeral 212 is a second substrate, reference numeral 213 is a lowerpolarizing plate, reference numeral 214 is an upper polarizing plate,reference numeral 215 is a liquid crystal layer, and reference numeral216 is a seal material. As shown in FIG. 4B, the X electrode 201 and theY electrode 202 are formed on the different parts of the structuralmember of the liquid crystal display panel. In addition, it ispreferable that the first substrate 211 and the second substrate 212have high optical transmittance.

Furthermore, generally, in an IPS type liquid crystal display panel, onthe surface of the liquid crystal layer side of the first substrate 211,from the first substrate 211 toward the liquid crystal layer 215, ascanning line (also referred to as a gate line), an interlayerinsulating film, a picture line (also referred to as a source line or adrain line), a thin film transistor (TFT), a pixel electrode, aninterlayer insulating film, a counter electrode (also referred to as acommon electrode), and an oriented film are sequentially formed.However, FIG. 4B does not show these components.

Furthermore, on the liquid crystal layer side of the second substrate212, from the second substrate 212 toward the liquid crystal layer 215,an optical shielding film, color filters of red, green and blue, aflattening film, and an oriented film are sequentially formed. However,FIG. 4B does not show these components.

In the structure of FIG. 4B, a back electrode formed on a surfaceopposite to the liquid crystal layer of the second substrate also servesas the X electrode 201, and the counter electrode Y also serves as the Yelectrode 202.

FIGS. 5A, 5B and 5C are views that show a detection principle of thetouch panel-integrated display device having the structure shown inFIGS. 4A and 4B.

FIG. 5A is a view that shows a state where the touch operation is notperformed, FIG. 5B is a view that shows a state where a finger 502approaches the touch panel 106, and FIG. 5C is a graph that shows achange of the detected signal.

As shown in FIGS. 5A, 5B and 5C, a voltage source 504 is connected toany one electrode (herein, the Y electrode 202) of the X electrode 201and the Y electrode 202, the pulse (the drive signal) is input from thevoltage source 504, and the transient current accompanied with the inputpulse from the voltage source 504 is detected in the detection circuits(505 and 506) via the other electrode (herein, the X electrode 201) thatperforms the capacity coupling. As shown in FIG. 5A, the capacitycoupling forms a line 501 of electric force between the X electrode andthe Y electrode.

As shown in FIG. 5B, when the finger 502 approaches the touch panel 106,the line 501 of electric force is cut off. Thereby, the transientcurrent is reduced.

As shown in FIG. 5C, when the finger 502 or the like comes into closelycontact with, the detection signal level detected in the detectioncircuits (505 and 506) is changed from a detection signal level 507before the contact shown in FIG. 5A to a detection signal level 508after the contact shown in FIG. 5B. A difference between the detectionsignal level 507 and the detection signal level 508 is detectionsensitivity.

In addition, as shown in B of FIG. 2C, since the detection signaldetected by each X electrode 201 is a plurality of pulse rows, thedetection circuits (505 and 506) accumulate the detection signals of theplurality of pulse rows. Specifically, the detection circuits integratethe detection signals by the integration circuit to detect the signalsof the detection signal level 507 and the detection signal level 508.

Hereinafter, in the touch panel-integrated display device, a type (amutual detection) of performing the high-precision coordinate detection,by the use of the change of the electrostatic capacity between thecounter electrode (the Y electrode 202 of FIGS. 4A and 4B) and thedetection electrode for sensor (the X electrode 201 of FIGS. 4A and 4B)by the influence of a finger of a user will be described.

FIGS. 6A and 6B are views that describe the mutual detection in thetouch panel-integrated display device.

As mentioned above, in the touch panel-integrated display device, thecounter electrode (the Y electrode 202 of FIGS. 4A and 4B) and thedetection electrode for sensor (the X electrode 201 of FIGS. 4A and 4B)are provided.

A mutual capacity 601 is formed between the electrodes. Herein, only onedetection electrode for sensor (Rx_n; the X electrode 201 of FIGS. 4Aand 4B) is noticed. Furthermore, six (Tx_1 to 6) counter electrodes (theY electrodes 202 of FIGS. 4A and 4B) are provided.

The counter electrode (the Y electrode 202 of FIGS. 4A and 4B) has anearth capacity 601. Herein, since the earth capacity of the detectionelectrode for sensor of Rx_n (the X electrode 201 of FIGS. 4A and 4B)has the electrode structure described in FIGS. 4A and 4B, substantialmutual capacity 601 is obtained.

In the touch panel control unit 108, a voltage control unit having apair of switching elements of S1 and S2 is provided with respect to eachcounter electrode (the Y electrode 202 of FIGS. 4A and 4B). Furthermore,herein, the voltage to be controlled is set to two voltage levels ofVtxh and Vtxl.

Furthermore, the detection electrode for sensor of Rx_n (the X electrode201 of FIGS. 4A and 4B) is connected to the detection circuit unit via apair of switching elements of S3 and S4. In addition, in FIGS. 6A and6B, the detection circuit unit is constituted by the integrationcircuit. Furthermore, in FIGS. 6A and 6B, the voltage level of thereference voltage of the integration circuit is shown by Vref, and thevoltage level of the output voltage of the integration circuit is shownby Vo.

Hereinafter, the control of the mutual detection will be described basedon the circuit configuration shown in FIG. 6A.

The basic operation of the mutual detection includes a reset period anda detection period. The detection is repeatedly performed in the unit ofthe basic operation, and the counter electrodes becoming the target (theY electrode 202 of FIG. 4) are sequentially changed. FIGS. 6A and 6Bshow a case where the counter electrode of Tx_1 in the counter electrode(the Y electrode 202 of FIGS. 4A and 4B) is a target.

The reset period is a period that resets the electric potential of thecounter electrode of Tx_1. At this period, since the switching element(S4) and the switching element (S2) are connected to each other, themutual capacity 601 is set to a state of being charged with the voltageof (Vref−Vtxl). In addition, in FIG. 6B, the voltage of the Vtxl isshown as 0 V.

Next, the switching element (S4) and the switching element (S2) enterthe open state together, and are shifted to the detection period.

In the detection period, first, the switching element (S3) is connected,and the input to the integration circuit is possible. After that, theswitching element (S1) is connected, and the electric potential of thecounter electrode of Tx_1 transits from the voltage of Vtxl to thevoltage of Vtxh. At this time, the electric current flows via the mutualcapacity 601. Since the electric current is integrated by theintegration circuit, the output voltage (Vo) of the integration circuitchanges.

Furthermore, since the electric current is proportional to the magnitudeof the mutual capacity 601, when there is a conductor such as a finger,the capacity thereof drops, and thus the electric current also drops.Thereby, since the output voltage (Vo) of the integration circuit alsochanges, the detection thereof is possible.

Thereafter, after the switching element (S3) is opened and theintegration circuit is detached, the switching element (S4) isconnected.

Thereafter, the switching element (S2) is connected. After that, thisoperation is repeated.

Hereinafter, in the touch panel-integrated display device, a type(hereinafter referred to as a self detection) of detecting whether ornot the measurement target approaches even if there is no coordinateinformation, by the use of the change of the earth capacity of thedetection electrode for sensor (the X electrode 201 of FIGS. 4A and 4B)by the influence of a finger of a user will be described.

FIGS. 7A and 7B are views that describe the control of the selfdetection of the present example in the touch panel-integrated displaydevice. Hereinafter, the control of the self detection will be describedbased on the circuit configuration shown in FIG. 7A.

The self detection period includes the respective periods of the resetperiod, the charge period, and the detection period. Herein, the controlof the switching element (S1) and the switching element (S2) isconcurrently performed in the entire counter electrodes (the Y electrode202 of FIGS. 4A and 4B; Tx_1 to 6). Furthermore, herein, only onedetection electrode for sensor (Rx_n; the X electrode 201 of FIGS. 4Aand 4B) will be noticed.

In the reset period, since the switching element (S2) and the switchingelement (S4) are connected to each other and the mutual capacity 601 isreset, the mutual capacity 601 enters the state of being charged withthe voltage of (Vref−Vtxl). Thereby, the electric potential of thedetection electrode for sensor of Rx_n (the X electrode 201 of FIGS. 4Aand 4B) becomes the voltage of Vref.

Next, the switching element (S2) and the switching element (S4) areopened together, and transits to the charge period. At this time, theswitching element (S3) and the switching element (S4) enter the openstate together, then the switching element (S1) is connected, and theelectric potential of the entire counter electrode (Tx_1 to 6) becomesthe voltage of Vtxh.

In the reset period, since the mutual capacity 601 is charged with thevoltage of (Vref−Vtxl), the electric potential of the detectionelectrode for sensor of Rx_n (the X electrode 201 of FIGS. 4A and 4B)becomes the voltage of (Vref−Vtxl+Vtxh) at the charge period. Inaddition, in FIG. 7B, the voltage of Vtxl is shown as 0 V.

When there is a finger or the like near the detection electrode forsensor of Rx_n (the X electrode 201 of FIGS. 4A and 4B), the change ofthe electric potential of the detection electrode for sensor of Rx_n(the X electrode 201 of FIGS. 4A and 4B) also concurrently charges theelectrostatic capacity formed between the finger and the detectionelectrode for sensor of Rx_n (the X electrode 201 of FIGS. 4A and 4B).

After the charge period, the period is shifted to the detection period.At this time, the switching element (S1) and the switching element (S3)are connected to each other, and the switching element (S2) and theswitching element (S4) are opened. When the switching element (S3) isconnected, the capacity between the detection electrode for sensor ofRx_n (the X electrode 201 of FIGS. 4A and 4B) and all the counterelectrodes (Tx_1 to 6), that is, the capacity corresponding to theelectric potential difference of (Vtxh−Vtxl) in the electric chargecharged in the mutual capacity 601, and the electric charge charged inthe electrostatic capacity between the detection electrode for sensor ofRx_n (the X electrode 201 of FIGS. 4A and 4B) and a finger or the likeis moved to the integration circuit. The output voltage (Vo) of theintegration circuit changes due to the electric charge.

Herein, when there is no finger or the like near the detection electrodefor sensor of Rx_n (the X electrode 201 of FIGS. 4A and 4B), since thereis no electric charge charged in the electrostatic capacity between thedetection electrode for sensor of Rx_n (the X electrode 201 of FIGS. 4Aand 4B) and a finger or the like, the amount of electric charge moved tothe integration circuit is small, and thus the output change of theintegration circuit becomes smaller.

Thereby, the self detection becomes possible. Thereafter, this operationis repeated.

FIGS. 8A and 8B are views that describe the detection state of the selfdetection of the present example in the touch panel-integrated displaydevice.

FIG. 8A shows a case where a finger or the like does not approach in thedetection period described in FIGS. 7A and 7B. The amount of electriccharge, which is read from the detection electrode for sensor of Rx_n(the X electrode 201 of FIGS. 4A and 4B), is an electric charge (Q1)that is charged due to the structure of the mutual capacity 601 or thelike.

FIG. 8B shows a case where a finger or the like approaches in thedetection period described in FIGS. 7A and 7B. The amount of electriccharge, which is read from the detection electrode for sensor of Rx_n(the X electrode 201 of FIGS. 4A and 4B), is a sum (Q1+Q2) of theelectric charge (Q1) charged due to the structure of the mutual capacity601 or the like and an electric charge (Q2) charged between thedetection electrode for sensor of Rx_n (the X electrode 201 of FIGS. 4Aand 4B) and a finger or the like. Thereby, it is possible to detect thepresent or absence of a detection object (for example, a finger) by thevoltage difference of the output voltage of the integration circuit.

In addition, since the integration circuit is provided for eachdetection electrode for sensor (the X electrode 201 of FIGS. 4A and 4B),in the self detection period, the output voltage (Vo) is output from theintegration circuit provided in each detection electrode for sensor (theX electrode 201 of FIGS. 4A and 4B), respectively.

In this case, for example, as the determination of the present orabsence of the detection object (for example, a finger), when the outputvoltage (Vo) that is output from one integration circuit of theplurality of integration circuits is a predetermined value or more, itmay be determined that there is a detection object, when the outputvoltage (Vo), which is output from the integration circuit more thanhalf of the plurality of integration circuits, is a predetermined valueor more, it may be determined that there is a detection object, or whenthe output voltages (Vo), which are output from all the integrationcircuits, are predetermined values or more, it may be determined thatthere is a detection object.

Hereinafter, a more specific configuration of the liquid crystal touchpanel-integrated display device of the example of the invention will bedescribed.

FIG. 9 is a perspective view that shows a more specific configuration ofthe liquid crystal touch panel-integrated display device of the exampleof the invention. A liquid crystal display device 100 shown in FIG. 9includes a liquid crystal display panel 1, a drive circuit 5, a flexiblesubstrate 70, a front panel 40, a storage case (not shown), and abacklight (not shown).

The liquid crystal display panel 1 has a TFT substrate 2 and a colorfilter substrate 3. The TFT substrate 2 and the color filter substrate 3are stacked each other at a predetermined interval, both substrates arebonded to each other by a sealing material (not shown) provided near aperipheral portion between both substrates, a liquid crystal compositionis enclosed and sealed inside the sealing material, and a polarizingplate is stuck to the outside of both substrates.

The TFT substrate 2 is provided with a counter electrode 21, and acounter electrode signal line 22 connected to the counter electrode 21from the drive circuit 5. The counter electrode signal can betransmitted from the drive circuit 5 to the counter electrode 21 via thecounter electrode signal line 22. The color filter substrate 3 isprovided with the detection electrode 31 (the X electrode 201 of FIGS.4A and 4B), and the detection electrode 31 is connected to a flexiblesubstrate 75 using a connection portion 77. The flexible substrate 75 isconnected to the flexible substrate 70 using a connector 80. Thedetection signal from the detection electrode 31 is transmitted to thedrive circuit 5 via the flexible substrate 75, the connector 80, and theflexible substrate 70.

In addition, the liquid crystal display panel 1 has a display unitincluding a plurality of pixels in a matrix form. The counter electrode21 is placed to face the pixel electrode in the pixel. By applying thevoltage between both electrodes, the orientations of the liquid crystalmolecules change. Along with the change of the orientation of the liquidcrystal molecules, the transmittance of light changes, and the image isdisplayed.

Next, the detection electrode 31 and the counter electrode 21 of theliquid crystal display device 100 shown in FIG. 9 will be describedusing FIG. 10.

As mentioned above, although the counter electrode 21 is provided on theTFT substrate 2, the counter electrodes 21 of plural lines (for example,about twenty) are commonly connected to both ends, and are connected tothe counter electrode signal line 22. The counter electrode signal issupplied to the fascicular counter electrode 21 from the drive circuit5.

In the liquid crystal display device 100 shown in FIG. 9, the fascicularcounter electrode 21 also serves as the Y electrode 202 shown in FIGS.4A and 4B, and forms the scanning electrode of the invention.Furthermore, the detection electrode 31 corresponds to the X electrode201 of FIGS. 4A and 4B, and forms the detection electrode of theinvention.

Thus, the counter electrode signal includes the counter voltage used forthe image display, and the drive signal (the input pulse voltage ofFIGS. 7A and 7B) used for the detection of the touch position. When thedrive signal is applied to the counter electrode 21, the detectionsignal is generated in the detection electrode 31 that is placed at afixed interval with the counter electrode 21 to form the capacity. Thedetection signal is taken out to the outside via the terminal 36 for thedetection electrode.

In addition, dummy electrodes 33 are formed on both sides of thedetection electrode 31. The detection electrode 31 forms the T-shapedterminal 36 for the detection electrode of expanded toward the dummyelectrode 33 side in one end portion. Furthermore, the TFT substrate 2is also formed with various wirings, terminals or the like such as theinput terminal 25 for the drive circuit, in addition to the counterelectrode signal line 22.

FIG. 11 shows an enlarged schematic cross-sectional view of a part ofthe cross section of the display unit in the liquid crystal displaydevice 100 shown in FIG. 9.

As shown in FIG. 11, a pixel unit 200 is provided on the TFT substrate2, and the counter electrode 21 is used for the image display as a partof the pixel. Furthermore, the liquid crystal composition 4 isinterposed between the TFT substrate 2 and the color filter substrate 3.The detection electrode 31 provided in the color filter substrate 3 andthe counter electrode 21 provided in the TFT substrate form thecapacity, and when the drive signal is applied to the counter electrode21, the voltage of the detection electrode 31 changes.

At this time, as shown in FIG. 11, when a conductor such as a fingerapproaches or comes into contact therewith via the front panel 40, thecapacity changes, and the voltage generated in the detection electrode31 changes compared to a case where there is no approach and contact.

In this manner, by detecting the change of the capacity generatedbetween the counter electrode 21 formed on the liquid crystal displaypanel 1 and the detection electrode 31, the liquid crystal display panel1 is able to include the function of the touch panel.

As described above, in the present embodiment, in the touchpanel-integrated display device, the detection circuit used for themutual detection can also be used for the self detection, and thus it ispossible to realize the miniaturization and the cost reduction of thecontrol IC.

As mentioned above, although the invention made by the inventors hasbeen specifically described based on the above-mentioned example, theinvention is not limited to the above-mentioned example, and, of course,can be changed within the scope that does not depart from the gistthereof in various forms.

While there have been described what are at present considered to becertain embodiments of the invention, it will be understood that variousmodifications may be made thereto, and it is intended that the appendedclaim cover all such modifications as fall within the true spirit andscope of the invention.

1. A display device comprising: a display panel; a touch panel controlunit; a plurality of scanning electrodes formed on the display panel; aplurality of detection electrodes that is formed on the display panel; adrive signal supply unit for inputting a drive signal to each of thescanning electrodes; and a detection unit for detecting a detectionsignal from each of the detection electrodes; wherein the touch panelcontrol unit supplies the driving signal to each of the scanningelectrodes from the drive signal supply unit for detecting a touchposition based on the detection signal detected from each of thedetection unit, and supplies the driving signal to the plurality ofscanning electrodes collectively from the drive signal supply unit fordetecting of the detection unit.
 2. The display device according toclaim 1, wherein the drive signal supply unit has a first switchingelement that supplies a high drive voltage to each of the plurality ofscanning electrodes, and a second switching element that supplies a lowdrive voltage to each of the plurality of scanning electrodes, thedetection unit has an integration circuit in which a reference voltageis input to one terminal, a third switching element that is connectedbetween each of the detection electrodes and the other terminal of theintegration circuit, and a fourth switching element that is connectedbetween each of the detection electrodes and the one terminal of theintegration circuit, the first switching element and the secondswitching element are provided for each of the scanning electrodes, andthe third switching element and the fourth switching element areprovided for each of the detection electrodes.
 3. The display deviceaccording to claim 2, wherein a touch position detection period has areset period and a detection period for each of the scanning electrodes,in the reset period in a scanning electrode of a scanning target towhich the drive signal is input, the first switching element of thescanning electrode of the scanning target is turned off, the secondswitching element of the scanning electrode of the scanning target isturned on, the first switching element and the second switching elementof the scanning electrode other than the scanning target are turned off,the third switching elements of all the detection electrodes are turnedoff, and the fourth switching elements of all the detection electrodesare turned on, the capacity between the scanning electrode of thescanning target and all the detection electrodes is charged with thereference voltage, in the detection period, the first switching elementof the scanning electrode of the scanning target is turned on, thesecond switching element of the scanning electrode of the scanningtarget is turned off, the first switching element and the secondswitching element of the scanning electrode other than the scanningtarget are turned off, all the third switching elements are turned on,all the fourth switching elements are turned off, and the electriccurrent flowing in the capacity between the scanning electrode of thescanning target and all the detection electrodes is integrated by theintegration circuit provided for each of the detection electrodes, andthe touch position detection unit detects based on the output voltage ofthe integration circuit provided for each of the detection electrodes.4. The display device according to claim 2, wherein the approachdetection period of the object to the detected has a reset period, acharge period, and a detection period, in the reset period, the firstswitching elements of all the scanning electrodes are turned off, thesecond switching elements of all the scanning electrode are turned on,the third switching elements of all the detection electrodes are turnedoff, and the fourth switching elements of all the detection electrodesare turned on, and the capacity between all the scanning electrodes andall the detection electrodes is charged with the reference voltage, inthe charge period, the first switching elements of all the scanningelectrodes are turned on, the second switching elements of all thescanning electrodes are turned off, the third switching elements of allthe detection electrodes are turned off, and the fourth switchingelements of all the detection electrodes are turned off, and thecapacity between all the scanning electrodes and each of the detectionelectrodes is charged with a sum of the reference voltage and the highdriving voltage, in the detection period, the first switching elementsof all the scanning electrodes are turned on, the second switchingelements of all the scanning electrodes are turned off, the thirdswitching elements of all the detection electrodes are turned on, andthe fourth switching elements of all the detection electrodes are turnedoff, and the capacity between all the scanning electrodes and each ofthe detection electrodes is integrated by the integration circuitprovided for each of the detection electrodes, and the approachdetection unit detects that the detection object approaches, based onthe output voltage of the integration circuit provided for each of thedetection electrodes.
 5. The display device according to claim 1,wherein the plurality of scanning electrodes and the plurality ofdetection electrodes are formed on different surfaces.
 6. The displaydevice according to claim 1, wherein one electrode of the plurality ofscanning electrodes and the plurality of detection electrodes is formedon a surface of an observer side of the display panel, and the otherelectrode of the plurality of scanning electrodes and the plurality ofdetection electrodes is formed on the inside of the display panel. 7.The display device according to claim 1, wherein the display panel is aliquid crystal display panel that has a first substrate, a secondsubstrate, and a liquid crystal layer interposed between the firstsubstrate and the second substrate, the second substrate is placed onthe observer side, one electrode of the plurality of scanning electrodesand the plurality of detection electrodes is formed on a surface of anopposite side to the liquid crystal layer of the second substrate, andthe other electrode of the plurality of scanning electrodes and theplurality of detection electrodes is formed on a surface of the liquidcrystal layer side of the first substrate.
 8. The display deviceaccording to claim 1, wherein the plurality of scanning electrodes andthe plurality of detection electrodes are stripe-shaped electrodes.